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Scrapie

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Scrapie is a fatal, degenerative disease that affects the central nervous system of

sheep and goats. It is classified as a transmissible spongiform encephalopathy.

Infected flocks typically experience significant production losses. The U.S. sheep and

goat industry continues to experience export losses and increased production and

disposal costs because the United States is not free of scrapie.
Scrapie is difficult to detect. It can take 2 to 5 years for an animal to show signs of

disease, and current diagnostic tests require brain or lymphoid tissue. Animals

typically live 1 to 6 months after they begin to show signs. Most are infected as

young lambs or kids, but adult animals can get it, too. Apparently healthy animals

infected with the disease agent can spread it.

What To Look For

Signs of central nervous system problems, most commonly incoordination or

poor muscle control (ataxia)

Weakness of any kind, including stumbling, falling down, or having difficulty

rising (not including animals with visible traumatic injuries and no other signs of

scrapie)

Behavioral abnormalities

Significant weight loss with no decrease in appetite or in an animal with

adequate teeth

Increased sensitivity to noise and sudden movement

Tremors

Star gazing

Head pressing

Abnormal gait that involves both the forelimbs or rear legs such high stepping

with forelimbs, bunny-hop movement with rear legs, or swaying of back end.

This does not include gait abnormalities involving only one leg or one front and

one back leg.

Repeated intense rubbing with bare areas or damaged wool in similar locations

on both sides of the animal's body or, if on the head, both sides of the poll;

abraded, rough, thickened, or hyperpigmented areas of skin in areas of

wool/hair loss in similar locations on both sides of the animal's body or, if on the

head, both sides of the poll

Less specific clinical signs:

Unable to walk prior to slaughter or death

Condemned antemortem at slaughter for non-central nervous systems signs

Poor body condition despite having good teeth
Unknown cause of on-farm death

Videos

Clinical Signs of Scrapie

Difficulty Eating

Gait Problems

Nibbling

Hopping Gait

How To Prevent This Disease

One of the best ways to prevent scrapie is to select genetically resistant breeding

stock. This practice has significantly reduced scrapie in the United States. Owners of

infected flocks should restock with resistant rams and resistant or less susceptible

ewes.

We also recommend the following biosecurity measures to reduce the spread of

scrapie:

1. Maintain a Closed Herd. Maintain a closed herd with no external contact with

sheep or goats. Minimize outside purchases of sheep or goats to reduce the risk

of scrapie exposure. Select replacement animals from another closed herd that

has measures in place to prevent scrapie introduction or that are genetically

resistant.

2. Reduce Exposure. Wash and disinfect boots that have been to facilities with

other livestock. After removing debris from surfaces, disinfect with a diluted

5.25% bleach solution (add 50 ounces bleach to 78 ounces of water to create 1

gallon of disinfection solution). Use personal protective equipment (PPE), such

as boot covers and gloves, and proper handwashing techniques when traveling

between livestock. Reduce commingling of herds in locations where livestock

come from various places (such as markets, fairs, or exhibits).

3. Confine Lambing and Kidding. Confine ewes and does that are lambing or

kidding so that there is limited contact with other animals. Remove any

placental tissues, fluids, and soiled debris as soon as possible after

lambing/kidding while wearing PPE. Disinfect the birthing area between births.

Ewes and does with unknown scrapie status should remain separated until
there is no vaginal discharge. Milk and colostrum from potentially exposed

sheep or goats should not be fed to lambs or kids.

How It Is Treated

There is no treatment for scrapie. To eliminate the disease from an infected flock or

herd, genetically susceptible exposed animals and animals showing clinical signs are

euthanized and the premises is cleaned and disinfected.

Prions are difficult to decontaminate as they have been shown to tightly bind to

surfaces without losing infectivity. They are resistant to most disinfectants including

alcohol and formalin. Prion contamination has also been shown to have resistance to

heat and radiation. While prion decontamination is difficult, there are methods that

can be used. For guidance on cleaning and disinfecting farm equipment and

premises, see Appendix 2 in the Scrapie Program Standards Volume 2 (708.43 KB).

Report Signs of Animal Disease

Producers or owners who suspect an animal disease should contact their

veterinarian to evaluate the animal or herd. Find an accredited veterinarian.

Animal health professionals (veterinarians; diagnostic laboratories; public health,

zoo, or wildlife personnel; and others) report diagnosed or suspected cases of

nationally listed reportable animal diseases to APHIS District Offices and to the State

animal health official as applicable under State reporting regulations. 

Eradicating Scrapie

National Scrapie Eradication Program

The National Scrapie Eradication Program (NSEP), a cooperative State-Federalindustry program, is working to eradicate classical scrapie from the United States

and meet World Organisation for Animal Health (WOAH) criteria for disease freedom.

To date, the program has eliminated scrapie in 99 percent of U.S. sheep and goats.

The program is conducting targeted sampling of subpopulations that have a higher
prevalence of scrapie than the general sheep/goat population to find the remaining

cases.

NSEP Standards (1.46 MB)

NSEP Annual Report

Modernizing NSEP

APHIS published a final rule in the Federal Register in 2019, updating scrapie

program regulations (9 CFR 79). The rule established a more flexible approach to

disease investigations and affected flock management and more consistent animal

identification and recordkeeping requirements for sheep and goats. The rule also

moved specific requirements for official eartags and official identification methods,

such as tattoos and implantable electronic ID (microchips), and indemnity

calculations to the NSEP Standards.

Surveillance

The NSEP surveys for scrapie in the United States. Surveillance components include:

1. Regulatory scrapie slaughter surveillance

2. Non-slaughter surveillance (for example, trace investigations, on-farm testing)

3. The Scrapie Free Flock Certification Program

Since 2002, the prevalence of scrapie has decreased significantly through existing

eradication efforts. This is largely due to effective slaughter surveillance of

geographically distributed sampling based on annual population estimates.

However, to declare the United States “scrapie free,” we must prove to the world

that we have conducted testing in all sheep and goat populations. That is why owner

submission of samples from sheep/goats over 18 months of age found dead or

euthanized on farm is extremely important. With the help of those who raise sheep

and goats, APHIS will be able to declare the U.S. free of scrapie. Scrapie currently

costs sheep and goat industries approximately $10 to $20 million in lost export

opportunities, annually.

National Scrapie Surveillance Plan (revised August 2022)

Scrapie Incentive Program

FY 2023 State Sheep and Goat Sampling Minimums

Submitting Samples for Scrapie Testing
Producers, accredited veterinarians, APHIS representatives, and State animal health

employees may collect and submit samples from adult sheep or goats. APHIS

provides shipping boxes and pre-printed, postage-paid labels at no cost to producers

and accredited veterinarians. APHIS will pay for scrapie testing of up to 30 animals

per flock per year. Producers may remove and submit whole heads or report

deceased sheep or goats and ask for help with submitting samples. Accredited

veterinarians can either remove and submit whole heads or collect and submit

specified tissues.

To request a box, or for more guidance on collecting and submitting samples,

contact the APHIS Veterinary Services District Office in your State or your State's

designated scrapie epidemiologist. 

Shipping Instructions

Whole head samples: Ship the cooler containing the head with frozen cold packs

overnight to Remington Locker, APHIS' sample collection facility:

18795 S 580 W Remington, IN 47977 

Phone: 317-347-3100 

Fax: 219-261-2357 

Email: remington.locker@usda.gov

Be sure to inform the facility of the shipment’s delivery date.

Tissue samples: Ship tissue samples to an APHIS-contract laboratory. Contact the

APHIS Veterinary Services District Office in your State for instructions.

Test Results

Positive test results will be confirmed by the National Veterinary Services

Laboratories (NVSL) or an NVSL-approved laboratory.

Indemnity

In 2021, APHIS published the USDA Commercial Indemnity Table, which supersedes

section II.J. 4. (a) of the Program Standards that detail how commercial sheep and

goat* indemnity values are calculated. The values are based on nationally
recognized market data sources including USDA's Agricultural Marketing Service,

USDA's National Agricultural Statistics Service, and the Livestock Marketing

Information Center.

* Certain classes of sheep and goats are not represented in this table. A process for

valuing these animals is still being finalized.

Genetic Susceptibility of U.S. Sheep and Goats

Approximately 30 percent of U.S. sheep are genetically susceptible to scrapie. Some

animals have been bred to be genetically resistant to the disease. Because scrapie

persists in the environment for years, owners of previously infected flocks should

restock with rams that are resistant and ewes of resistant or less susceptible

genotypes. 

Currently all goat breeds are considered genetically susceptible. Researchers are

still investigating the possibility of genetic resistance in goats but have not yet

identified a resistant genotype.

Major Codons Associated With Scrapie in Sheep

Codon 171 is the major determinant of classical scrapie susceptibility in the United

States. It plays a role in sheep susceptibility to the major type of classical scrapie

found in the United States, valine-independent scrapie.

It codes for the amino acids Glutamine (Q), Arginine (R), Histidine (H) or, rarely,

Lysine (K).

Q is associated with increased susceptibility to classical scrapie, while R is

associated with increased resistance.

H is considered to have the same susceptibility as Q. The relative

susceptibility of K is still under investigation. Therefore, both H and K are

reported as Q by most laboratories and are treated as Q for regulatory

purposes.

Over 99 percent of the classical scrapie cases in the United States that

have been genotyped were QQ.

Codon 136 plays a role in sheep susceptibility to the less common type of classical

scrapie found in the United States, valine-dependent scrapie.
It codes for the amino acid Alanine (A), Valine (V) or, rarely, Threonine (T).

V is associated with increased susceptibility to classical scrapie.

The occurrence of T is extremely rare and as of September 2012 has never

been reported in the United States. Because its role in susceptibility is

unknown, if it were identified in U.S. sheep it would be reported by most

laboratories as V and treated as V for regulatory purposes.

Codon 154 plays a minor role in classical scrapie and is not often used in the United

States as part of a breeding or regulatory strategy. It is, however, associated with

increased susceptibility to Nor98-like scrapie.

Codon 141 is associated with increased susceptibility to Nor98-like scrapie. Its role in

classical scrapie, if any, is unknown.

Codon 112 also plays a minor role in classical scrapie, although its association with

classical scrapie resistance is still under investigation.

Testing for Genetic Susceptibility

Genotype testing for susceptibility to scrapie is a key component of NSEP. Note:

Genetic testing does not tell you whether a sheep or goat is infected with scrapie.

Sample submissions must meet the following requirements for official genotype

testing:

Sheep or goats are officially identified.

The blood is drawn by a Federal or State animal health official or an accredited

veterinarian.

The sample is submitted with a VS Form 5-29 or State equivalent to an APHISapproved lab.

The sample meets any additional requirements set by the APHIS-approved lab.

Becoming an APHIS-Approved Genotyping Laboratory

Approved genotyping laboratories may conduct privately funded official scrapie

genotype testing and compete for NSEP-funded official genotyping. This approval

lasts for 1 year and is subject to review and renewal.
Each laboratory must apply to conduct official genotype tests. Interested labs should

send an application package to the NVSL. The application must contain the following

information about the laboratory:

Laboratory name and address

Name of the legally responsible official and, if different, the director of the

laboratory

A description of the laboratory facilities and equipment that will be used in

performing genotype tests

A list of the types of samples that will be tested

The standard operating procedure for each test to be used, including methods,

materials, equipment, and other relevant information

A list of the names of individuals performing specific tests and a detailed

statement of each individual’s qualifications

A detailed description of the procedures to satisfy the recordkeeping

requirements of the Scrapie Eradication Program

A description of the specific procedures for reporting test results

The laboratory quality assurance manual

A statement authorizing APHIS to inspect the laboratory without notice during

normal business hours (inspection may include, but is not limited to, reviewing

and copying records, observing tests being conducted, and interviewing

personnel)

After submitting a complete application package, the laboratory will have additional

tasks such as completing a proficiency test panel and site visits to demonstrate

technical competency and evaluate testing and laboratory protocols. Following

completion of these tasks, APHIS will extend approval in writing to the laboratory.

For more information, contact scrapie@usda.gov.

Scrapie-Free Flock Certification Program

The National Scrapie Flock Certification Program (SFCP) increases the marketability

of sheep and goats from flocks that have demonstrated freedom of scrapie disease

by adhering to program standards. This is a voluntary program for producers who

are committed to monitoring their flocks for clinical scrapie signs and reporting any

suspect animals for testing. Participants in this program benefit by decreasing the

risk of introducing classical scrapie into their flocks.
Participants may participate in one of two categories in the SCFP program:

1. Export Category—Monitors and samples participating flocks. If conditions are

met, it may lead to Export Certified status and recognition of negligible scrapie

risk.

2. Select Category—Test samples from mature sheep and goats to identify and

remove infected flocks.

How To Apply

To participate in the SCFP program in either category you must complete the SFCP

application form (VS Form 5-22).

Note: The Export Category has additional documentation requirements for applying

such as a flock inventory and an initial flock inspection.

For more information on this voluntary program, including how to enroll, please

contact scrapie@usda.gov.

Educational Materials

Video: National Scrapie Eradication Program (NSEP) and the Importance of

Sheep and Goat Traceability

Official USDA Sheep and Goat Identification: A report on the quantity and

number of orders for official identification (ID) distributed to or purchased by

sheep and goat stakeholders

Sheep & Goat Official ID Basics Flow Chart

Key Points for Livestock Market Operators (PowerPoint) (pdf)

Factsheet on Sheep and Goat Identification Requirements

Finish the Fight Against Scrapie Poster

Finish the Fight Against Scrapie - Arabic

Finish the Fight Against Scrapie - Chinese

Finish the Fight Against Scrapie - Farsi

Finish the Fight Against Scrapie - Hindi

Finish the Fight Against Scrapie - Portuguese

Finish the Fight Against Scrapie - Turkish

Finish the Fight Against Scrapie - Vietnamese

National Institute of Animal Agriculture Materials
Goat ID Flyer: (high resolution for printing) (smaller size file for email)

Sheep ID Flyer: (high resolution for printing) (smaller size file for email)

Sheep and Goat ID Requirements (PowerPoint) (pdf)